According to this National Geographic article, Cambridge researchers have recently uncovered "mineralized networks of blood vessels" and "ripples" tracing the "wrinkled outer layer of the cortex" of an Iguanodon-like dinosaurs in rocks initially found in 2004 on a beach in Sussex, England. The article also describes how a "pickling" process (e.g., bodies found in bog) might have led to this improbable and unique discovery. Enjoy!

The original paper is available here.

The original paper is available here.

I planned a search for that paper later. I appreciate your sparing me the effort. It's a thrilling find.